Influence of a Standard Heat Treatment on the Microstructure and Properties of Inconel X‐750 Produced by Laser Powder Bed Fusion

The production of nickel-base superalloys through powder bed fusion using alaser beam (PBF-LB) offers a promising method for reducing the cost of aeronauticalcomponents, especially those with complex geometries. However, whenthese materials are processed using PBF-LB, the standard heat treatmentsdeveloped for conventional manufacturing routes do not consistently yieldpredictable microstructures or mechanical properties. Thus, this study analyzeshow PBF-LB affects the microstructure and mechanical behavior of Inconel alloyX-750 when compared to a hot-rolled counterpart after undergoing a standardprecipitation-hardening heat treatment (solution annealing, stabilization, andprecipitation). Microstructure is examined using analytical electron microscopyand high-energy X-ray diffraction, while mechanical behavior is assessed throughmicrohardness. Significant differences between both manufacturing routes aredetected, so that PBF-LB processing led to an increase in grain size, anisotropy,fraction of low-angle grain boundaries, mean angle of misorientation, and dislocationdensity. Moreover, PBF-LB promoted the formation of γ0-Ni3(Al,Ti) andη-Ni3Ti phases during solution annealing and stabilization, respectively. Notably,the formation of γ0 contributes to an anomalous microhardness increaseobserved between these steps. These findings suggest that PBF-LB may inhibitrecrystallization and facilitate precipitation during heat treatment, therebyaffecting the performance of components produced using this technology.